repair with cfrp active strengthening

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NEWSREPAIR WITH CFRP

Active strengthening

Tanks: cryogenic tests

Stonecutters Lifting

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hig

hli

gh

ts

FACTS&TRENDS 5Large span roofs: First for Czech Republic 6

Tartastan: Repeat success 7

SUSTAINABLEDEVELOPMENT 4Quality: ISO9001:2000 for VSL China

The Quality Management System

of VSL China has been certified ISO 9001:2000

by the British Standard Institution, BSi. 4

SITE INSIGHTS 16Spain: Barcelona buzz 16

Canada: Double first 18

Dubai: VSL at the Ritz 21

Hong Kong: Tricky truss transfer 22

RSA: Full speed for Gautrain 24

COVER STORY 8Repair and strengthening with CFRP:

Advanced active strengthening

The VSL has added an advanced active

strengthening system to its wide range

of construction and engineering products

and services. This eco-friendly tool

is CarboStress®.

SPECIAL REPORT 26Cryogenic Tests: Think Tanks with VSL’s Gc

Successful cryogenic tests demonstrate that

VSL’s Gc anchorages are fit for use in cryogenic

applications such as LNG & LPG tanks.

NEWS, magazine published by VSL International Ltd. • Bern, Switzerland Director of Publication: Jean-Philippe Trin • [email protected] Editor in chief: Jane

Rousseau • [email protected] Editor : Elisabeth Lichter-Rodriguez • [email protected] Co-ordinators: Carlos Such, Renata Tamburrino, Doris

Tong. Distribution: Sandra Puel • [email protected] Design: Red Line Photos: Derek Allan, Jane Rousseau, Laurent Zylberman, others Copyright: VSL •

TECH SHOW 28Hong Kong Hoist

High competencies, innovative heavy lifting

solutions and flexibility were necessary for the

complex operation on Stonecutters Bridge.

Cover photo: Stonecutters Bridge, Hong Kong

ANCHORAGES26

CABLES19

CFRP 8

DAMPERS5

HEAVY LIFTING 28

VSLNews2-2007 30/11/07 16:03

EDITORIALI S S U E T W O • 2 0 0 7

The VSL difference

J e a n - P h i l i p p e T r i n , C E O

Our clients expect VSL to provide real technical added value

which guarantees a quality and on-time project. This added

value is brought about by the commitment and

professionalism of our teams, at both the tendering and

construction phases. During the preparatory phase, our

technical centres in Switzerland and Singapore ensure that

effective methods are developed which can be relied on.

Our R&D teams continually monitor and improve the products

used on site whilst our construction teams ensure that the

works are carried out to specification and in an effective and

safe manner.

Our proven management procedures and their strict application differentiate VSL.

We are committed to manage our operations and expand our business using these

strengths and values.

VSLNews2-2007 30/11/07 16:03

V SL China’s QualityManagement System hasbeen certified by the

international certification body BSIas meeting ISO9001:2000. Theinitiative was driven by VSL’smanagement to bring aboutimprovements in performancethrough the implementation of anISO9001-certified system. VSLChina applied to upgrade its ISO certificate at the request of VSL’ssenior management and its clients.BSI carried out the assessment inmid-August 2007 and confirmedthat VSL China meets all elementswithin the scope of its registration(manufacture of post-tensioningcomponents and equipment) andthe requirements of the

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4

SUSTAINABLE DEVELOPMENT

QUALITY MANAGEMENT

ISO9001:2000 for VSL China VSL China has successfully applied for the

ISO 9001:2000 certification to improve further its

competitiveness, competence and profitability.

have been introduced to ensurequality and compliance with VSL International’s requirements.As a BSI-certified factory and VSL Group-approved ManufacturingCentre, VSL China has more andmore products which are approvedfor export. These include itemssuch as multistrand SC and GCanchorages, slab anchorages andwedges, all produced in line withVSL Group’s objectives: quality,standardisation and compatibility. �

management standardISO9001:2000. VSL China’s qualitysystem has been developed withthe help of VSL International andCTT (VSL’s manufacturing centrelocated in Spain). ManufacturingQuality Plans have been created forall components. These define theinspection and testingrequirements including aspectssuch as control methods andacceptance criteria. New testingequipment and inspection tools

H ong Kong is beginning oneof the world’s largest cleanwater rehabilitation

programmes and Insituform AsiaLimited (IAL) is well positioned tomeet the demands. Its innovativetrenchless technologies are idealfor use in one of the most denselypopulated cities on earth. InSeptember, IAL began work withmajor local contractor Paul YConstruction Company Limited ona new three and a half yearmaintenance contract for sewerrehabilitation in the Northern NewTerritories. IAL, which has beenoperating in Hong Kong for almosttwo years, has continued to workfor the Water Supplies Department(WSD) under a sub-contract to local contractor U-TechEngineering Limited. Work hasalso been undertaken for the MassTransit Railway Corporation,repairing saltwater mains that

SEWER REHABILITATION

Insituform demonstratesits merits

provide cooling for the airconditioning systems in somestations. IAL has also recently beenasked to provide demonstrations ofits PolyFold (see picture) andPolyFlex systems to consultantMaunsell AECOM, acting on behalfof the WSD, prior to use in watercontracts. �

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5

NORMS

Top marks for VSL-CTTstructuralbearings

C TT Stronghold has receivedCE mark approval forelastomeric and pot

bearings with the CTT and VSLbrands. VSL has also obtained alocal mark of approval in Portugalfor certified structural bearingproducts. The new standards forstructural bearings have beencompulsory throughout theEuropean Union since January2007. All structural bearings mustcarry the CE mark in compliancewith the EU Construction ProductsDirective 89/106/CEE concerningthe standardisation of products. To meet the new regulations priorto applying for the award of the CE mark, CTT Stronghold adaptedall of its bearing designs and its manufacturing process as soon as the new standards forelastomeric and pot bearings werepublished (EN 1337-3:2005 and EN 1337-5:2005). Requirementsfor individual bearings are criticalto their intended use and so thecompany applied for theattestation of conformity system 1.This involved audits by acertification body and initial typetests at an official laboratory, bothapproved by the EuropeanCommittee for Standarisation(CEN). �

FACTS&TRENDS

Dampers

VSL and SRI extend agreement

> VSL Taiwan and VSL Hong Kong

have entered into Exclusive

Distributorship Agreements withSumitomo Rubber Industries (SRI)for the use of Gensui dampers inbuilding applications. Theagreements, which were finalised inJanuary and April 2007 respectively,extend the original DistributorshipAgreement with SRI, which appliedonly to cable-stayed bridgeapplications. The continuedcollaboration between SRI and VSLis aimed at extending VSL’s coveragein the rapidly-growing market forvibration control in buildings. Frequent earthquakes and seasonaltyphoons in Taiwan create a strongdemand for vibration controlsystems such as dampers and baseisolation, especially for high-risecommercial and luxury residentialbuildings. VSL has secured threebuilding contracts since the SRIGensui Damper was introduced to

the Taiwan market in 2007.Installation of the dampers – thefirst to be used in buildings outsideof Japan - will take place in 2008.SRI and VSL’s damper businessdevelopment is proving successful in

other parts of the world as well asHong Kong and Taiwan. Dr. Matsumoto from SRI gave apresentation introducing theadvanced vibration control system todelegates at the XVI NationalCongress of Seismic Engineeringheld in Vallarta, Mexico from Oct 31to Nov 3, 2007, a major seismicengineering conference. � Contact: [email protected]

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6

FACTS&TRENDS

Slabs

New step in Chilean market> An impressive 100,000m2 of

slabs have been completed in justfour months at a new shoppingmall in Chile. Slab construction forthe Mall Alameda in Santiago deChile was awarded to VSL, whichhad proposed a very efficientsystem. The design involves post-tensioned flat slabs, whichincorporate shear connectorsdesigned by VSL to resist punching.Use of Nelson stud shear railscontrols the punching and allowscolumn heads to be eliminated. A further benefit is that installationis very straightforward, as theNelson system is simply nailed tothe formwork. The absence ofcolumn heads and beams allowsthe use of simple formwork. �

Contact: [email protected]

> VSL CZ has introduced to the

Czech Republic its assembly

method for the large-span roofswidely used on aircraft hangars. The 1,400t roof for a new aircraftmaintenance hangar in Mosnovwas first assembled on the groundready for the 35m lift to its finalposition. Lifting of the 140m by83.5m roof was carried out with 14 SLU 120/500 hydraulic liftingunits, which were located on top ofthe permanent columns. The liftwas controlled with the Bravosystem, allowing permanentmonitoring of the lifting force anddisplacement. The successfulexecution of the project was aresult of close cooperationbetween the designer Excon, clientHutni Montaze, VSL CZ and VSLHeavy Lifting. VSL sees considerablepotential for applying the methodto other hangars scheduled forconstruction in the region.� Contact: [email protected]

Large span roofs

First for Czech Republic

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7

Keystone® walls

First for Hong Kong

> Exactly two years after the

completion of its first stay cable

bridge in Kazan, VSL Switzerlandhas carried out the installation,stressing and tuning of 16 stays for the Kazan 2 Bridge. The firstbridge was handed over at the City of Kazan’s millenniumcelebrations. This new bridge,which is parallel to the first one,was designed by Moscow’sGuiprostransmost design instituteand constructed by NUR-1, one of the leading contractors inTatarstan. The parties involved –the client, engineer, maincontractor and subcontractorsincluding VSL - were the same asthose on the first bridge. Close co-operation has enabled a verysuccessful project, to the fullsatisfaction of the Government of Tatarstan. The completion of the

Tatarstan

Repeat success

> VSL Hong Kong is carrying out

a complete installation package

for Hong Kong’s first Keystonewall. The 130m-long and 16m-highwall is already generating interestfrom other potential clients. Itforms part of site formation worksfor a residential development atDiscovery Bay on Lantau Island.

The Keystone modular block-facing provides an attractive finishto the reinforced fill block whilstpermitting the easy inclusion ofcurves, foundation steps andplanter walls into the structure. Automated production blocksenabled the coloured facing blocksfor the entire project to be castwithin three days. VSL Hong Kong -working for main contractor ChinaOverseas Civil Engineering -proposed Keystone, an alternativeto a tiered grey panel faced wall.The solution was selected by clientHong Kong Resort Company Ltd.as it offered improved aestheticswhilst allowing to withstand higherbuilding loads. This enabledadditional apartments to be builtabove the wall. � Contact:

[email protected]

Buildings

Pune marketgrowing in India

> The Pune region in India has

been an important market forVSL’s PT in buildings activities inIndia ever since the first contractwon in 2000. Since then, VSL hascompleted more than 170 projectsin Pune of which more than 125 projects have been done withthe well-known local consultant YS Sane associates. The total area post-tensioned by VSL is1,600,000m2 with over 7,000 tonnesof PT strands consumed. VSL hasalso worked on projects with otherleading consultants such asSterling Engineering & HansalParaik Associates. VSL’s majorclients include Magarpatta,Infosys, I-flex, Wipro, Kolti Patildevelopers, DLF-Akruthi, KPITCummins & Godrej Developers. At present, VSL is working on 35 jobs with a total post-tensionedarea of 350,000m2 and consumingup to 175t of PT strand eachmonth. In Pune, many newtownships, IT parks and shoppingmalls are to be built in the nearfuture and VSL is aiming to be anintegral part of the building post-tensioning works in many of thesedevelopments. � Contact:

[email protected]

latest bridge project in thisRussian Federation republic hasfurther strengthened VSL’sposition there.� Contact:

[email protected]

VSLNews2-2007 30/11/07 16:03

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COVER STORY

8

REPAIR AND STRENGTHENING WITH CFRP

Advanced active stren

VSLNews2-2007 30/11/07 16:03

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engthening

9

A s structures continue toage, there will be increaseddemand for proven means

of evaluating and repairingreinforced and/or prestressedconcrete. Years of service andexposure may have left thesestructures in need of substantialrepair, restoration andstrengthening. Similarly, bridgestrengthening may be required inorder to accommodate increasedlive loads, changing designrequirements or upgraded codes.Strengthening is also useful insituations such as wherestructures have suffered damageor deterioration, where defectshave come to light, where thestatic load system has changed,where a structure is subject to excessive deformation orcracking, or if its design life needsto be extended.

Active versus passiveStrengthening techniques arecategorized as passive or active,depending on how the loadsinteract with the retrofittedmaterials that are applied to thestructure. Passive systems are

VSL has added an advanced active strengthening

system to its wide range of construction

and engineering products and services.

This eco-friendly tool is CarboStress®, a post-

tensioning system which takes full advantage

of the outstanding properties of carbon

fibre reinforced polymer

(CFRP) materials.

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R E P A I R A N D S T R E N G H T E N I N G W I T H C F R P

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COVER STORY

applied when no participation instress-sharing is required and the retrofitting material is onlyengaged when additional loads are applied and/or additionaldeformation occurs. Traditionalmethods of passive strengtheninginclude section enlargements,steel plate bonding and the external bonding of fibre-reinforced polymer materials tothe structure. Stress in the existingsteel reinforcement is often the limiting factor for a passivestrengthening system. Unloadingthe structure prior to the

VSL’s repair &strengthening services

• Concrete forensics • Advanced concrete repair• Passive strengthening

- Bonded CFRP (design & application)- Bonded SRP – Hardwire®

(design & application)• Active strengthening

- External post-tensioning- CarboStress® post-tensioned CFRP

• Protection- Ductal® - Blast mitigation- Dampers - Vibration mitigation- Cathodic protection - Corrosion mitigation

The VSL CarboStress® system is acarbon fibre post-tensioning system. Theload from the CFRP plate is transferredvia a steel anchorage into the structure.The actual connecting element of theelement to the structure is either a steelshear pin or a steel plate. The tensioningoperation of the CFRP tendon is done on thestressing anchorage. Several types ofanchorages can be used.

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11

application of a passive system isnot always possible or mayincrease the overall project costs.

An active system will be requiredin situations where thestrengthening technique isrequired to reduce the stressimmediately by sharing theexisting loads. Traditional methodsof active systems include externalpost-tensioning (PT) using stressbars or PT strands grouted inHDPE (high-density polyethylene)pipes. While these active systemshave proved to be effective, theconstruction detailing, wet works,duration and heavy equipmentinvolved are often majorconsiderations in terms of the inconvenience to users andresulting costs.

The CarboStress® Post-TensionedCFRP System developed jointly byVSL and Sika requires only minordemolition work in the form ofconcrete coring for the load-transfer dowels. The CFRP plates

are then mounted onto the structural member via theanchorages and then stressed.

Not only does the system savetime and reduce inconvenience to users, but it is also more eco-

Rapid strengthening without disruption at

Xiaofeng Railway Bridge, Changsha, China

The Xiaofeng Railway Bridgein Hunan Province wasselected as a pilot project to demonstrate theeffectiveness and simplicityof the VSL CarboStress®

System. The bridge is asimply-supported structurewith three 20m-long spans.Engineers had observednumerous vertical cracklines extending from thebottom to the topthroughout each beam.

After extensive laboratory tests by the owner, Beijing Guangdong Rail Line,the structure was strengthened using 18m of CarboStress® tendons on each side of the beams. The installation process caused no disruption to the rail service.

Mounting of CFRP tendon

into anchorage

Longitudinal strengthening of Sung San Bridge

deck, Seoul, Korea

Large transverse cracks were detected at several locations in the deckslab of this multi-span bridge. Analysis determined that they were the result of an increase in traffic loading beyond that for which the longitudinal reinforcement had originally been designed.

The VSL CarboStress® Systemwas chosen for the longitudinalstrengthening. Steel saddleswere installed to deflect the CFRP plates in order to prevent debonding at thehaunches.

friendly as demolition is minimaland there is no requirement fortraditional construction materialssuch as concrete, reinforcing bars and aggregates.

PT maximising CFRP’sbenefitsFiber Reinforced Compositematerials have differentmechanical properties -E modulus,and tensile strength- and combinedwith different resins such as epoxyor polyester, they form a widerange of FRP composites: Carbon(CFRP), Glass (GFRP) or Aramidfibre (AFRP). Aramid fibre has highstrength resistance, and is mainlyused to produce bullet resistant and other body armor products.Glass fibre is mainly used inconstruction against earthquake,and to provide ductility.

Carbon fibre reinforced polymerswere developed in the late 1960sand have been applied extensivelyfor structural strengtheningaround the world. The last decadehas seen further developments intheir use as post-tensioned

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12

COVER STORY

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strengthening tendons forapplication on bridges and other structures.

The CarboStress® Post-TensionedCFRP System was developed to provide owners with a highly-advanced system for strengtheningvarious types of structures. It can be used on bridges, civilstructures, commercial and private properties, industrialand manufacturing facilities as

Structural strengthening of Clinton & Hopkins Bridge, Ohio, USA

well as petrochemical, oil and gasplants, tanks, culverts. It may beused for restoring or enhancingearthquake resistance or forstrengthening any additionalopenings required in existingstructures under conversion.

This advanced system is based onthe principle of non-bondedexternal prestressing and consistsof CFRP tendons with concentratedforce transfer at the plate ends.

The basic elements of the systemare made up of the CFRP plate,two CFRP stress heads, a steeldead-end anchorage and a steellive-end anchorage, where thestressing will be carried out.The load from the CFRP plate istransferred via the steelanchorages into the structure. The actual connection between the anchorage and the structure ismade by either shear pins or steelplates. The CFRP tendon is then

The structure is a multi-span bridge consisting of 16 prestressed precast boxes which had then beenconnected on site. A leaking and defective drainagesystem had resulted in premature corrosionpropagating on the prestressing strands. The CarboStress® System was applied successfully to supplement the damaged bending reinforcement and

to restore the structural strength of the bridge. CFRPfabric was also used to strengthen the anchorage zonesfor the CarboStress® System because of the slenderdesign of the box girders. This project received the 2004Award of Excellence for the Transportation Category bythe ICRI (International Concrete Repair Institute).

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13

installed onto the anchorages andthe stressing is carried out at the live anchorage. Whilst theanchorage has several standardoptions, it can also be easilyadapted to suit project specifics.

The post-tensioning of CFRPplates prevent prematuredebonding of the externally bondedstrengthening system and itmaximizes their outstandingmaterial properties.

Live traffic scenariosThe selection of an appropriatestrengthening system for a bridgerequires a detailed conditionsurvey, the definition of futurerequirements, the determination of alternative approaches,evaluation of the solutions andfinally the development of thespecifications and methods. The high flexibility of theCarboStress® anchorage designenables engineers to configure thesystem to suit specific scenarios.The thin CFRP plates also enable

Transverse strengthening of A3 Escher Canal Bridge deck, Glarus,

Switzerland

tendon cross-overs. In addition, the short load transfer of theexternal PT force through the shearpin strengthens the structureimmediately upon stressing.

This system was developed withtoday’s on-site challenges in mind:in most strengthening scenarios,the work has to be executed underfull – or, at best, reduced – livetraffic levels. The available timeframe in such scenarios is usuallylimited and challenging. The CarboStress® tendons are

This three-span prestressed box girder bridge on the A3Sargans-Zurich Motorway was built in 1957. It crossesthe Escher Canal near Wesen. During an inspection in1964, a crack running the whole length of the bridgewas observed in the centre of the underside of the deckslab. All that could be done was for engineers to monitor it continuously until a viable solution couldbe found. It was not until the development of CFRPplates that a plan was made to strengthen the deck slabtransversely for both negative and positive moments.

In addition, CarboStress® was applied to the undersideof the deck, to act as an external prestressing system.The tensioning force was transferred to the concreteonly at the anchorages at the ends of the plates. The positioning was calculated to achieve the maximumstrengthening effect.A highway authority approval was needed, hence anexternal witness audited how each tendon was tested to +10% of its working load before it was installed andstressed on site.

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lightweight, at just 3.5kg per 10mroll, and can be moved easily byrolling. This is particularly usefulin areas where access conditionsare tight. In addition, theinstallation is fast and easy withoutthe need for sophisticatedspecialist equipment. In temperateclimates, the non-bonded systemmay be applied without the need for any additional curing equipment.

The CarboStress® system hasproved to be a success and iscatching interest. Engineers andowners are looking for an activestrengthening solution withminimal disruption to servicesand/or when traditional activestrengthening systems are notpractical or possible. In thisrespect, VSL is one of the fewspecialists in the world to havecarried out extensive testing of post-tensioned CFRP platesystems and proven them in the field. �


COVER STORY

Extending the life of a bridge in Grindelwald,

Switzerland

The Tschingeley Bridgeover the Luetschine is a50-year-old bridgeconnecting the well-knownwinter resort stationGrindelwald with its wastedisposal plant. The 30m-long structure is post-tensioned with 12 tendons,each made up of sevenwires of 7mm diameter.Increasing lorry weights meant that the bridge’s carrying capacity was nolonger sufficient and had to be improved. Retrofitting measures includingexternal post-tensioning have been carried out with the aim of extending

the bridge’s life by 10 years. VSL’s CFRP CarboStress® System waschosen because of its inherent advantagesincluding corrosion resistance and lightweight. A total of eight CarboStress® tensionmembers - two on each side of the twowebs - were installed and stressed inOctober 2007. Each tendon consists of 60mm x 2.4mm CFRP plates(Sika®CarboDur S624) with a working load of 220kN. The tendons are bonded to thestructure, enabling it to carry heavier trafficthan before.

Seismic upgrade of a nuclear power plant in Switzerland

The Gösgen nuclear power plant was commissioned in 1979 and producesnearly 8 billion kilowatt hours of electricity per year, which represents about15% of the total Swiss electricity consumption. The emergency feed buildinghad to be strengthened as part of a general seismic upgrade as the fourdeionized water tanks in which the reactor coolant is stored, did not meet thelatest design standards. The tank walls had to be strengthened with asecondary strengthening system using prestressing techniques. To avoidrestricting the operation of the plant, the strengthening works on each basinhad to be completed in only two days. Surface strengthening which could beapplied in just a few hours was therefore necessary. The ideal solution was CarboStress® with chemically resistant CFRP plateswhich could be applied in a very short time. They were also able toaccommodate the transfer of tensioning forces at the ends of the plates,through concentrated end anchorages into the cross walls.

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15

COMBINING ADVANCED AND TRADITIONAL METHODS

VSL continues its pursuit of creative engineering solutions in thefield of Repair and Strengthening, providing ingeniouscombinations of traditional methods and advanced composites. The following projects illustrate some of the scenarios which VSLhad been directly involved to produce long-term, durable and costeffective repair & strengthening solutions for the industry.

Successful bridge pier repairs in Spain with AFRP

A new high speed railway bridge near Gironarequired additional pier cap reinforcement due to an error made during construction. The reinforcement has to fulfil all engineeringrequirements – in particular, 6,000kN ofhorizontal force – as well as aesthetic anddurability criteria. The solution combinesexternal post-tensioning using 0.6'' (15mm)strand with a CTT Connector and high-performance protection. A thixotrophic mortar

with corrosion inhibitor is used, together withexternal AFRP (Aramid Fiber Reinforced Polymer)reinforcement to control mortar cracking. Ananti-carbonation coating conceals the 30mmreinforcement that has been added.

Externally bonded CFRP

for Spanish railway bridge

A pair of bridges has beensuccessfully repaired byVSL and local contractorIRECA using a techniquethat combines the use ofexternally-bonded CFRPand post-tensioning

systems. Cracking of the pier cap may have been initiatedby poor construction, and made worse by environmentally-induced degradation. Repairing the pier caps has involvedrestoring durability using epoxy injection, improvingstructural behaviour through external post-tensioning andcontrolling surface cracks by bonding CFRP laminates andsheets. The project has maintained the bridge’s aesthetics.Benefits of using composites for the strengthening includedimmunity to corrosion and light weight for easy applicationat height. This avoided the need for extensive scaffoldingand reduced the labour costs. CFRP’s availability in virtuallyany size and length simplifies its use. Although the fibresand resins are relatively expensive compared to traditionalstrengthening materials, the labour and equipment forinstallation are greatly reduced. Access requirements arealso much simpler. Further work is planned on the bridge:carbon fibre tendons will be installed on some of the piersover the coming months under an experimentalprogramme, supervised by a university and several national concrete institutes.

Saving by sawing on the Fozières Viaduct, France

Located in the South of France on the A75 motorway, the Fozières Viaduct consists of three 40m-long spansand was built in the eighties. Large cracks on the deck supporting beams due to chemical reactions caused bythe high temperature of the concrete after pouring during its youngage were observed during inspections. The bridge deck load wastransferred by computer-controlled hydraulic jacks on temporarysupports fixed on the existing pile. The existing cross-beam wassawed into 14 elements of 15 tons each and then lowered to theground. The new beam (90m3) was poured after reinforcement andformwork installation. The bridge deck load was then transferredfrom the temporary supports to the new bearings. Repair works onthe second column were carried out in the same way. The motorwayreopened to the traffic after six months of works.

VSLNews2-2007 30/11/07 16:03

> Barcelona is famed for its

architecture, and manyinternationally-renownedarchitects such as J. Nouvel, A. Isozaki, Toyo Ito, Z. Hadid, D. Chipperfield, D. Perrault,Alonso-Balaguer, Richard Rogersor C. Ferrater are making theirmark there with exciting newprojects. The boom has enabledVSL to work with major structuralconsultants to develop solutions tohelp realise the distinctive designsthrough key elements as largespans, cantilevers, transfer slabs,etc. A prime example is VSL’scooperation with the structuralconsultants for the Richard Rogers

project, “Las Arenas”, where thesite of a former bullring, built in1898, is being transformed into amajor leisure and entertainmentcomplex. VSL carried out a key partof the works to retain its distinctiveNeo-Mudéjar façade, includingstabilisation and load transfer.Additional extensive slab post-tensioning has also been carriedout for the civil contractorDragados. Another current schemeis Arata Isozaki's D38 officedevelopment, probably one of themost challenging buildings underconstruction in the city. Slabs withclear spans of 15x22m andcantilevers up to 15m have been

> VSL Chile is nearing

completion of a 31m-high VSoL®

wall in Santiago for the RadialNor-Oriente road, which is beingbuilt by Sacyr. The wall isconstructed in two levels and has atotal area of 2,600m2. Chile’sresurgence in road construction is

leading to increased demand for retained earth walls, reversingthe slow-down of the last twoyears. VSL Chile is targeting the new projects in order tomaintain its market leadershipwith this product.� Contact: [email protected]

Chile

High-level walls in Santiago

Spain

Barcelona buzz

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SITE INSIGHTS

16

projected with a combination ofwaffled and ribbed post-tensioningslabs together with edge post-tensioned beams to solve transfersand cantilevers. � Contact:

[email protected]

VSLNews2-2007 30/11/07 16:03

> High-speed production has

been achieved in the supply ofVSoL® retained earth walling to

> A new crossing of the Limpopo

River is the first single box girderbridge ever to be launched inMozambique, and the only one in southern Africa to have 50mspans. Portuguese contractorTeixeira Duarte is nearingcompletion of the bridge, whichhas been eagerly awaited as the original had been destroyeddecades ago. The contractor andthe designer, Lisconcebe, chose to use incremental launching forthe concrete deck. VSL Portugal

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17

defined the method, designedtemporary works and supervisedoperations. Its scope also includes the supply of 200t of post-tensioning steel as well asspecial ILM bearings andexpansion joints. It took just fivemonths to complete the launch of the 490m-long deck, using twoVSL lift-push jacks with a totalhorizontal capacity of 640t. Finalwork is taking place on the PT,bearings and expansion joints. �Contact: [email protected]

Mozambique

Limpopo first

Spain

VSoL® for Ferrolmeet challenging targets on a roadscheme in Ferrol. Structures onthe 15km project include fourviaducts and 12 mechanically-stabilised earth walls. CTT Stronghold was awarded thecontract to design and supply15,000m2 of VSoL® at 2,000m2 permonth. Faster deliveries were laterrequested to speed up the projectand production was increased toachieve a peak of 4,600m2 permonth. Owner of the scheme is Spain’s ministry of civil worksand the contractor is FCCConstrucción. � Contact:

[email protected]

Long span. The 900m-long

multi-span I-64 Kanawha River

Bridge in Charleston is being

constructed by the cast-in-situ

balanced cantilever method.

The bridge’s 231m main span

will be the longest for a concrete

box girder in the USA. VSL was

selected by Brayman

Construction Company to supply

the post-tensioning elements,

including some 984t of 0.6"

diameter (15mm) post-

tensioning steel. Enhanced

durability requirements have led

to the use of VSL's PT-PLUS™

plastic ducts.

Pier retrofit. VSL in the USA

continues work on the Huey P

Long Bridge Widening Project

in Louisiana. Its responsibility

includes supply and installation

of 101t of 0.6” (15mm) strand for

the retrofit of the piers used to

support the widened bridge.

VSL will work on five piers

with heights ranging from

32m to 42m.

Double benefits. VSL Australia

has completed work on two

large circular waste water

treatment tanks with precast,

post-tensioned walls, each

consisting of outer and inner

walls, located at the Boyer paper

mill in Tasmania and at

Gippsland Water Factory in

Victoria. VSL’s scope of works in

Tasmania was the wall design,

the supply and installation of

post-tensioning, while work in

Victoria consisted of panel

supply, the supply and

installation of post-tensioning.

Mock-up. On VSL’s nuclear

containment mock-up under

construction in France, VSL

will soon begin the first

demonstrations to the client for

nuclear applications regarding

the waterproofing, adjustment

and placing of different type of

ducts: VSL PT-Plus™, low friction

steel sheet duct, steel tubes.

N O T E P A D

VSLNews2-2007 30/11/07 16:03

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SITE INSIGHTS

Canada

Double first

> VSL is currently well under

way with work on the signaturespan stay cable bridge over thenorth arm of the Fraser River in Vancouver, British Columbia,Canada. When completed, the bridge will become part of the Canada Line Light Rail System. The new structure consists of anextradosed precast segmental box-girder bridge with a continuousdeck of 562m and a 180m precastsegmental main span. The mainspan provides clearance for the150m-wide main navigationchannel. Client for the scheme isRSL Joint Venture, made up ofRizzani de Echer and SNC Lavalin.The crossing will become NorthAmerica’s first extradosed cablestay bridge and its first to use theGensui dampers - this type ofdamper has already been used onmore than 40 bridges in Asia. Themain advantages over traditionaldamping systems are that they areeasy to install, require almost no

> Innovative techniques have been

incorporated into the new Wal-MartDistribution Centre, which wasinaugurated in June at Chalco inMexico. It includes the latestgeneration of racking systems,designed to achieve the maximumpossible storage capacity.

maintenance and have very littletemperature and frequencydependency. VSL in Spain andVStructural (VSL’s licensee in theUSA) have joined forces to supplythe VSL Stay Cable system(anchorages for 61 strands 0.6) aswell as the Gensui dampers for the bridge. The joint venture’sresponsibilities include full-timetechnical assistance on site. Thebridge also features a 139m-wide

VSL Corporation Mexico contributedto the project by constructing a180mm-thick bonded slab-on-grade,with an area of 7,000m2, for a keysection of the depot. This technologywith its inherent advantages isincreasingly popular in Mexico. �Contact: [email protected]

Mexico

Innovations for Wal-Mart

side span, two 45m-high main pylonsand two approach piers on each sideof the river’s north arm. The pylonsabove deck at the main piers aredesigned in steel and provideanchorage for the extradosed main-span tendons. The bridge is alsodesigned to carry a pedestrian/cycleway. Construction of the firstpylon was completed in August2007 and the works are scheduledfor delivery in spring 2008. �

VSLNews2-2007 30/11/07 16:03

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19

> VSL Denver has recently

provided and installed a bonded

post-tensioning system for theLegacy Parkway Pedestrian Bridgejust outside Salt Lake City, Utah.VSL was hired by WadsworthConstruction to provide the ECI6-19system for the construction of thecast-in-place, single-cell box girderbridge. The strand installation wascarried out by the push-through

> VSL Corporation Mexico has

been involved since February withthe structural design andinstallation of the PT system forthe 16 tanks at the residual water

Mexico

Refined solution

USA

Pushing through 245m

method and the post-tensioningwas completed ahead of schedule.The dramatic bridge starts parallelto the parkway before twice turningthrough 90° to finish parallel on theother side. It has an overall lengthof 245m, with post-tensioningrunning continuously over sevenpiers without intermediatestressing anchorages.� Contact: [email protected]

treatment plant for Pemex’sFrancisco I Madero refinery in Madero, Mexico. The tanks wereconceived as post-tensionedstructures, including thefoundations which consist of pileslinked by post-tensioned beamsand a slab post-tensioned withVSL’s Bondtec System. Both,vertical and horizontal post-tensioning was applied to thewalls, using EC5-7 and EC5-6 unitsrespectively. The height of the18,000m3 tanks is about 11m, with internal diameters of 46m and a wall thickness of 0.4m. � Contact:

[email protected]

VSoL® record. Record

installation speeds are being

achieved for the VSol® walls

on an access route to the new

Tanger Mediterranée port in

Tangiers. VSL was awarded the

design, supply and erection

of more than 24,500m2 of VSol®

walls with polymeric

reinforcement. The walls are

being erected in a record time

of just six months under the

direction of contractor SGTM.

Special jack. Post-tensioning work

using more than 2,000t of strand is

carried out by VSL Middle East for

the widening of Al Garhoud Bridge

in Dubai. Stressing forces on the

larger tendons of up to 8,500kN

and the restricted work space

required the use of VSL’s

12,500kN-capacity special

stressing jack. Client for the

project is the Road & Transport

Authority, Belhasa Six Construct is

the contractor and Halcrow Intl.

Partnership is the consultant.

Luxury slabs. VSL Middle East is

undertaking PT work for the

Khalidiya Palace Rotana Hotel &

Residences project in Abu Dhabi.

The scheme consists of four

blocks, with up to 24 levels of

post-tensioned flat slabs, using

more than 700t of strand. Client

for the scheme is Sheikh

Mohamed Bin Khalid Al Nahyan,

the consultant is Khatib & Alami

Consolidated Engineering and

the contractor is Nurol General

Contracting LLC.

Lucky 13. VSL Middle East was

awarded the post-tensioning work

for the precast segments of the

13 Bridge project in Bahrain. The

project involved the construction

of precast post-tensioned bridge

units in steel moulds and used

EC 6-19 anchorages and 1,100t

of strand. There are 378 segments,

each about 16m long and 7m

wide. Post-tensioning work

was completed three months

ahead of schedule.

N O T E P A D

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20

SITE INSIGHTS

Czech Republic

Express cabling

Switzerland

Holding back the shield

> VSL has used its SSI 2000 Stay

Cable System to achieve a dramaticreduction in the installation time forthe cables on a new Czech bridge. It took VSL only 28 days instead ofthe 56 days originally scheduled.This shortening of the originalschedule was achieved by advanceinstallation of anchors,prefabrication of HDPE pipes andstrands on site in combination withthe strand-by-strand method. Thebridge crosses the River Odra andAntosovicke Lake on new section ofD47 Highway close to the Polishborder. Total length of the bridge is592.7m, with a suspended 201m-long deck supported by a 46.8m-high central pylon. The stay cablesystem consists of 14 cables oneach side, ranging from 23m to99m. Nearly 140km of strands wereinstalled. The local design officeStrasky, Husty and Partners

designed the bridge and VSL’sclient was the main contractor,Skanska. The project is financed byRSD CR, the Road and MotorwayDirectorate of the Czech Republic.

VSL worked closely with the clientto achieve the faster cableinstallation, as the task was on theoverall project’s critical path. � Contact: [email protected]

> A hard rock tunnel boring

machine (TBM) has been put backon track thanks to an innovativesolution from VSL Heavy Lifting. The TBM had hit unexpected softsoil during the construction of thehighway tunnel de Moutier in theSwiss Jura mountains. Steering ofthe TBM became impossiblebecause of the resulting reduction inthrust force. VSL Heavy Lifting wasasked to provide a means of holdingback the top of the shield duringTBM operation. The solution thatwas developed consisted of twoSMU-120/550 Strand Moving Unitsand custom-made controls designed

to apply a constant retaining force ofup to 1,440kN, regardless of theTBM speed, which varied from zeroto 60mm/min. New for this project isfully-automated operation of theSMUs. This allows the TBM to movecontinuously while the SMUs re-gripevery 500mm. Load cells at theanchorages provide continuousreadings and an automatedemergency stop if necessary.Another first is the record-breaking435m strand length. A similaroperation had been successfullycarried out in 2002 on the DublinPort Tunnel. � Contact:

[email protected]

VSLNews2-2007 30/11/07 16:03

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> VSL is installing more than

300t of post-tensioning for thenew Technical Library Project inPrague in the Czech Republic.When completed, it will be thelargest post-tensioned building in the region. Construction consistsof six post-tensioned levels usingthe SO 6-4 bonded slab systemwith a total of 2,200 stressing andpassive anchorages. The floor planis a 75m by 75m “rounded square”,with each floor cast in six parts. A typical span is 15m by 15m andthe 300mm-thick flat slabs sit on6m-diameter caps on the

> VSL Switzerland has completed

the installation of 300t of post-

tensioning on behalf of Somagecat the Jorf Lasfar site, 150kmsouth of Casablanca. This projectis the result of a long-termbusiness relationship between VSLand Somagec, one of Morocco’sleading construction companies.Work consists of the constructionof 2,000m of sea-water pipelineand a balance tower. The 300mm-thick prestressed concrete pipelinehas an internal diameter of 2.5mand is post-tensioned transverselyand longitudinally. This pipe isused to supply sea water to aphosphoric acid factory. It is madeup of 22 independent sectionsconnected to each other byexpansion joints. Transverse post-tensioning is provided by sheathedmonostrand, making an average ofthree loops, and VSL 6-1anchorages. Longitudinally, post-tensioning of each 100m-longsection is achieved through theuse of VSL EC6-12 anchorages.The balance tower is a hill-toppost-tensioned concrete chimney,which is designed along the sameprinciples as the pipe. �

Contact: k.doghri@bouygues-

construction.com

Morocco

Sea-waterpipeline

supporting columns. Floor heatingand wiring are installed togetherwith the rebar and tendons. The six month project is due forcompletion at the end of 2007, withone floor completed every month.Main contractor for the scheme isa joint venture of Metrostav andOHL ÎS. � Contact: [email protected]

project is Hyder and the maincontractor is a joint venture ofBouygues Bâtiment and TargetConstruction. The total PT floorarea is approx. 80,000m2. More than550t of 0.6” (15.7mm) diameterstrand will be used and the tendonsare stressed with SO 6-4 slabanchorages. Floors are typicallydivided into four pours and built to a14-day cycle. VSL’s scope of workincludes slab and beam design,drawing production, supply of allthe post-tensioning materials andspecialist equipment, together withthe provision of specialistsupervision. � Contact: [email protected]

Czech Republic

Record library

> VSL Middle East is nearing

completion of post-tensioning

works for client Union Propertiesat the Ritz Carlton Hotel &Apartments project in Dubai. Theproject consists of 15 levels of post-tensioned flat slabs, with transferbeams with multi-strand tendonslocated at the podium level for thehotel block and at two levels of theapartment block. Consultant for the

Dubai

VSL at the Ritz

VSLNews2-2007 30/11/07 16:03

> VSL’s Climbform has now

reached the top of the 300m-highprestigious One Island Eastbuilding in Hong Kong’s QuarryBay. VSL designed and suppliedthe Climbform to build the centralcore in an operation which startedin early December 2006. A four-day climbing cycle was achieved informing the walls for the totalclimbing operation, whose area

> FT Laboratories, a subsidiary

of VSL International, has

completed two 18-month projects

using a state-of-the-art roboticsystem to monitor railway tracksand issue alerts if they wereaffected by nearby constructionwork. The Automatic DeformationMonitoring System (ADMS)consists of computer-controlledrobotic theodolites, whichautomatically monitor surveyprisms. The system operates 24 hours a day, 7 days a week, andthe results are delivered online. It is typically used to monitor criticalstructures, such as railways andviaducts that are adjacent toconstruction work or excavations.The latest projects involvedmonitoring tracks for KowloonCanton Railway Corporation. Five automatic theodolites wereinstalled, together with 650 surveyprisms, and their movements weremonitored for 18 months. Theresults were reported continuouslyat four hourly intervals, with SMSand e-mail alerts sent outautomatically if unusualmovements were detected. �Contact: [email protected]

Hong Kong

Tricky truss transfer> VSL HK has been awarded a

subcontract for a complex andchallenging operation of lifting andlaunching four main roof trusses fora bridging link needed as part of theexpansion of the HK Convention andExhibition Centre. The new rooftrusses each weigh between 1,200tand 1,500t and span 90m across aharbour channel, at 27m from oneanother. They are supported on

Hong Kong

Robotskeep watch

Hong Kong

Soaring core

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22

SITE INSIGHTS

totals approximately 141,000m2.VSL was also awarded the design,supply and installation contract for66 post-tensioned floors, totalling112,000m2. The 285m-thick post-tensioned floor slab in a typicalfloor spans 13m from theperimeter edge beam to thecentral core. Again, a four daycycle was achieved. � Contact:

[email protected]

bearings on top of columns at 41mand 57m above ground level. Thefirst two, A and B, are assembled atthe position of C and D respectively,then launched sideways by 54mover the existing link bridge.Trusses C and D will then beassembled beneath their finalpositions. VSL has designed thetemporary works to enable thetruss installation. The lifting

support structure is made of self-balancing lifting brackets mountedon temporary concrete corbels,which in turn are stressed to the topof the permanent columns. Thetrusses are lifted by SLU330 strandjacks. Next stage is the installationof sliding beam supports, allowingthe load transfer. The sliding beamsand the trusses will then belaunched in alternate stages bystrand-jacking to the next columngrid before being raised into place. � Contact: [email protected]

intrafor.com

VSLNews2-2007 30/11/07 16:03

> Replacement of a 150t

generator on the Thatoom Power

Station has been successfullycarried out by VSL Thailand in a carefully-planned three dayoperation using the H450 frame.VSL Thailand was contracted toremove the existing generator andinstall a new one. The entire fast-track project was completed in just70 days, from signing thesubcontract to demobilising the site- including fabrication, internationaltransport, installation and the liftitself. The operation involved liftingand lowering the equipment by12m, as well as longitudinal andtransverse sliding. The project’sshort timescale was achievedthanks to the adaptable design ofthe H450 installation frame. �Contact: [email protected]

> Intrafor is using the directional

coring technique to drill holes ofalmost 700m and 1,300m as partof the ground investigation for ahuge tunnelling project in HongKong. The Harbour Area TreatmentScheme (HATS) is an extension of the earlier Strategic SewerageDisposal Scheme (SSDS). The aimis to upgrade the water quality ofVictoria Harbour. The main worksconsist of a series of sewagecollection tunnels, drop shafts and pumping stations around the northern coastline of Hong KongIsland and a cross-harboursewerage tunnel leading to a treatment plant atStonecutters Island. Groundinvestigation involves drilling

Hong Kong

Long holes on course

Thailand

Fast-track lift

Macau

Cotai climb

India

Compact solution

> The 9.5km Bangalore-Hosur

Elevated Expressway is built bythe precast segmentalconstruction method, using self-launching overhead gantries. The work is carried out as apublic-private partnership on aBOT (Build-Operate-Transfer)basis by Bangalore ElevatedTollway Limited, with three leadcompanies: Soma, Nagarjuna

inclined directional core holesalong the future tunnel alignments.Gammon Construction Limitedwas awarded the contract for three directional core holes, two of which were sublet toIntrafor in January 2007. �Contact: [email protected]

N E W S N ° 2 • 2 0 0 7

23

Construction Company andMaytas. VSL is responsible for allthree launching gantries, fromtheir design and fabrication toerection and operation. The scopeof work also includes constructionengineering and post-tensioning ofthe deck. As the structure is builtin the middle of a busy highway, it was not feasible to erect thegantries using cranes. VSLproposed a solution using VSL SLU-120s mounted on twoVSL Heavy Lifting towers erectedbehind the piers to raise eachgantry. The gantry main trussesand upper cross beams wereassembled at ground leveltogether with the lifting winch andancillary equipment and thetrusses were lifted simultaneouslyinto position. Pier segments andother components were liftedusing the winch. The truss wasthen locked into position ready forsegment erection. � Contact:

[email protected]> Form systems from VSL are

proving a great success in theconstruction of six towers for fourhotels at the Venetian Orient andCity of Dreams resort projects onMacau’s Cotai Strip. VSL-IntraforHong Kong was appointed by Hsin Chong Construction and theLeighton-China State-John HollandJV respectively to design, supply,supervise and commission six setsof formwork for the two projects.Four sets of Climbform and twosets of Jumpform are being used to construct the towers, the tallestof which will reach 159m whencompleted. Work started on bothsites in May 2007 and two sets of Climbform at Venetian Orient had completed their fifth climb by early August. � Contact:

[email protected]

VSLNews2-2007 30/11/07 16:03

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SITE INSIGHTS

Malaysia

Heavyweight travellerfor light vessel> Form travellers that are among

the most massive ever designed

have been used on a new bridge inBanting, Selangor. The bridge overSungai Langat is intended to providesufficient clearance for light vesselsserving local industries, especiallyMegasteel, replacing two existingbridges. The cast in-situ bridge - a prestressed double-cell box girderstructure – will cross the river with asingle 135m-long span. Constructionis by the balanced cantilever methodusing two pairs of form travellers,

precast beams. In total, the structureuses 384t of prestressing strands.The design was standardised touse 6-19s tendons for both thecantilever and the span tendons,with the longest measuring 120m.VSL is also supplying and installingelastomeric bearings andmechanical pot-bearings. �Contact: [email protected]

> Intrafor, in joint venture with

local partner Basil Read, hassuccessfully completed theconstruction of diaphragm wallsfor the Park and Sandtonunderground stations as part ofthe Gautrain project. The 80kmrailway will link Johannesburg,Pretoria and OR TamboInternational Airport in time forthe 2010 soccer World Cup.Intrafor excavated 17,000m2 ofdiaphragm wall up to 1.2m-thick,installed 2,845t of steelreinforcement and placed14,200m3 of concrete. Shear pininstallation and rock fissuregrouting were also within thescope of the project, which wascompleted in August. Challenginggeology and the need to completethe project in time led Intrafor tomobilise specialist equipmentfrom Hong Kong, in the form oftwo 80t rigs using cable-operatedclamshells and a new BC40/BG40trench cutter. � Contact:

jeanchristophe.gillard@vsl-

intrafor.com

RSA

Full speed for Gautrain

which carry a maximum concreteweight of approximately 375t. VSL’sscope of work includes the designand engineering for the box girderand precast beams; form travellerdesign and equipment supply;construction engineering for thebalanced cantilever work; and supplyand installation of prestressing forthe main-span box girder and

VSLNews2-2007 30/11/07 16:03

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25

Australia

Mutual support> VSL Australia is assisting

Abigroup Contractors with theconstruction of Alfords Point Bridge,a 445m-long incrementally-launched double-cell box girderbridge in a southern suburb ofSydney. VSL’s scope of workincludes the supply, installationand operation of the launching and braking system used for the 21 launches. The systemuses ZPE670 launching jacks andSMU330 braking jacks. VSL is alsoproviding post tensioning (169t), 8 rock anchors and elastomericbearings to the project. To providebetter continuity of site labouronce each cycle of post-tensioningworks are complete, VSL assistsAbigroup with formwork and steelfixing operations. Abigroup thenassists VSL by providing ‘top up’labour on the critical stressing andlaunching days. � Contact:

[email protected]

> Bank Negara Malaysia – the

country’s central bank – hasoutgrown its current premises andis expanding into new buildings.VSL has carried out prestressingwork on one of these, the FinancialServices and Resource Centre. The oval-shaped building consistsof six floors of offices and fivebasement levels. The structure isbuilt using a beam and slabsystem, with a mix of prestressing,reinforced concrete and somesteel structural elements.Construction involved close

coordination to accommodatespecialist requirements in thebuilding. VSL was responsible for detailing of the prestressing, as well as carrying it out during a 10-month period which wassuccessfully completed in July 2007. � Contact:

[email protected]

Malaysia

Big bank

> The Albury Bypass project

commenced in October 2005. VSL’sinitial involvement for the maincontractor Abigroup Contractors PtyLtd was the supply and delivery of4,133m2 VSoL® reinforced soil wallsfor four railway embankments. Thiswas increased to 9,759m2 with theaddition of East Albury section. Thisproject was the catalyst for settingup VSL’s precast yard in Holbrook70km North of Albury in NSW. VSLwas later awarded the supply andinstallation of 28 stay bars, rangingfrom 28 to 74 meters. The bars weremanufactured by VSL in Melbourne,transported to the paintingcontractor then to site at Albury. �Contact: [email protected]

Australia

From VSoL®

to staysMalaysia

SubangKelana link> VSL Malaysia and a joint

venture partner, Projalma, have

been awarded a contract for thecasting and erection of 747 precastsegments, the supply andinstallation of 1,100t of post-tensioning at the Subang KelanaLink, an elevated viaductconsisting of 34 spans of precastsegmental twin-cell box girders.The viaduct is built by the free-cantilever method and segmentsare lifted up in pairs by VSL’sstrand lifting units. The greatestchallenge faced was that the 20m-wide segments had rather thinconcrete sections. To protect themfrom cracking duringtransportation, most requiredfitting with supporting propsbefore setting out on the 200km-long journey from the casting yardto the site. The segments adjacentto the pier have also beenstrengthened by temporarystrutting and increases to thebottom slab thickness, so thatgantry loads could be transferredto the crosshead. The segmenterection works covered the designand supply of the launching girder,the falsework installation anddismantling for the cantilevers and provision of all labour and supervision for both thelaunching girder operation. VSLwas furthermore responsible for all aspects of the constructionengineering. � Contact: [email protected]

VSLNews2-2007 30/11/07 16:03

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26

SPECIAL REPORT

During the last two years, a total of five cryogenic tests have been

successfully conducted using VSL’s newly developed Gc anchorages

in Switzerland and Korea in accordance with ETA guidelines and

FIP recommendations(*) demonstrating that VSL’s Gc anchorages are

fit for use in cryogenic applications such as LNG & LPG tank projects.

Starting in 2004, countries such asChina and Korea have been engagedin a fast track LNG developmentprogram with China alone requiring100 tanks in the coming 15 years.Specifications set by keyinternational Engineer Procure &Construct (EPC) contractors such asCB&I, Whessoe Oil & Gas and IHIrequire the post-tensioning systemfor the tank structures to becompliant with the cryogenic criteriaof ETAG 013 Guidelines and with FIP recommendations.

In November 2005 VSL conductedits first cryogenic test on the newlydeveloped Gc 6-27 anchorage atempa’s laboratory in Switzerland for CBI who is the EPC contractorfor the Fujian LNG project in China.The 27 strand anchorage waschosen as it represented themaximum strand number for themost common anchorage sizesused in the design for large LNGtanks from 150,000m3 to 200,000m3

which typically range from 12 strands through 27 strands.

European standards,international witness Subsequent to the success of theGc anchorage in the Fujian LNGproject, which mainly opted forcomponents of European origin,VSL conducted further cryogenictests at Daewoo’s laboratory inSeoul, Korea, using components

Cryogenic Tests

Think Tanks with VSL’s Gc

* ETAG 013 Guidelines for European Technical Approval of Post Tensioning Kits for Prestressing of Structures, June 2002 and FIP recommendations for theacceptance of post-tensioning systems, 1993

Expected rupture of strand at ultimate load

during cryogenic tests

VSLNews2-2007 30/11/07 16:03

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27

from VSL’s manufacturing centre in Hefei, China as well ascomponents from Korea, Australiaand Thailand to suit the needs ofthe projects which may sourcecomponents from those countries.

In all tests, the post-tensioninganchorages were exposed tocryogenic temperatures byinjecting liquid nitrogen (-196°C)into the Gc anchorages. Each testwas performed in an official

laboratory and has been witnessedby experts from Chicago Bridgeand Iron (CB&I) or from theLaboratoire des Ponts etChaussées (LCPC).

Tests Summary

Cooling of dead end anchorage by injecting liquidnitrogen N2 into cryogenic chamber during 10 cycles loading, Daewoo Laboratory, Seoul

Group so as to become lessdependent on Argentinean gassupply. The main contractor is CBIfrom the USA whilst the local civilcontractor is EI Montajes. Whencompleted, these tanks will be thelargest ever built in South Americawith VSL’s type Gc anchorages usedfor both vertical and horizontaltendons. VSL in Chile and Spain willjoin forces to carry out worksscheduled for 2008 and 2009.VSL India has so far successfullycompleted 3 LNG tanks in Dabhol,2 in Dahej and 2 at Hazira forDabhol Power Corporation,Petronet LNG Ltd and Shell Ltdrespectively with the ongoningworks on a further 2 LNG tanks inDahej. All tanks are approximately80m in diameter and 40m in heightwith both horizontal and verticalpost-tensioning. �

tensioning of 2 LNG tanks of160,000m3 each in Quintero, Chile.This project is promoted jointly byEmpresa Nacional del Petróleo,Endesa Chile, Metrogas and BG

Date Anchorage units and strand grades Laboratory

Nov 05 VSL Gc 6-27, 1860N/mm2 empa, Switzerland

Jan 07 VSL Gc 6-27, 1770N/mm2 Daewoo, Seoul Korea

Jan 07 VSL Gc 6-27, 1770N/mm2 Daewoo, Seoul Korea

Mar 07 VSL Gc 6-27, 1860N/mm2 Daewoo, Seoul Korea

Jul 07 VSL Gc 6-27, 1860N/mm2 Daewoo, Seoul Korea

Plastic Trumpet performs well

under cryogenic conditions

Immediate benefitsAs a result of the successfulcryogenic tests, VSL is nowsupplying and installing the post-tensioning systems for a number ofLNG projects in Asia and America:Fujian LNG Project Phase 1, China;Shanghai LNG Project Phase 1,China; Pyeong Teak LNG ProjectPhase 2, Korea.VSL has been awarded the post-

VSLNews2-2007 30/11/07 16:03

28

TECH SHOW

Stonecutters lifting

Hong Kong hoistVSL Hong Kong has recently completed works on

Stonecutters Bridge to erect the steel decks of what

will be one of the longest cable stayed bridges in the world.

High competencies, innovative heavy lifting solutions

and flexibility were necessary.

N E W S N ° 2 • 2 0 0 7

The Stonecutters Deck Erection contract

The Alliance with the Maeda–Hitachi–Yokogawa–Hsin Chong JV wasresponsible for the erection of the steel back spans as well as for providingthe erection equipment for the main span. The back spans, weighing 4000teach, create the installation platform for the erection of the 1018m long steeldeck spanning over Hong Kong’s Rambler Channel at the access to thecontainer terminals. The Alliance model applied to this contract due to thenecessary flexibility for both VSL and the Joint Venture to tackle thetechnical challenges of what proved to be a very complex operation at theinterface of the three critical project areas – the concrete deck, the concretetowers and the steel deck. The full integration of the project teams allowedthe development of an optimized temporary works scheme utilizing thepartially completed permanent works wherever possible to support thetemporary works in order to minimize the steel quantities.

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VSLNews2-2007 30/11/07 16:03

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Off-load the back span and

slide into assembly position

Segments weighing between 120tand 300t have to be off-loaded at aspecially constructed jetty. A 54mlong cantilevering unloading frame isconnected to the tower shaft with ahinged connection and supported bytwo pairs of stay cables. A SLU-330strand jack is mounted on a sledgewhich slides along the beam drivenby a long stroke hydraulic jack. The14 segments are placed on speciallydesigned carts which slide firstperpendicular and then parallel tothe bridge axis in order tomanoeuvre them around the tower.

1

TECH SHOW

S T O N E C U T T E R S L I F T I N G

Define deck lifting sequence

Each deck has to be first liftedby 70m and subsequently slid by 6mtowards the tower and 2m towards theconcrete back span in order toovercome the geometric constraintsdue to the sloping tower face and thefalsework under the concrete backspan. The cross girders connecting thetwo carriageways can only be erectedafter completion of the main lift.

2

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31

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Carry out temporary works for the erection of the steel back spans

The lifting system comprises of two cable stayed brackets attached to the main bridge tower and a cantilevering lifting frame resting on thecompleted concrete back span. The tower brackets are formed by 28m longtwin steel box girders supported by a corbel at the tower shaft and twoplanes of stay cables. The stay cables have to be gradually stressed duringthe load build-up in order to control the deflections. The lifting strandbundles are anchored in horizontal beams pre-stressed to the steel deckwhich also provide the sliding surface for the longitudinal 2m deckmovement. The rear lifting frame consists of a large cross beam slidingalong a pair of cantilever beams. All strand jacks are mounted on sledgeswhich can be moved 6m transversally by horizontal SLU-70 jacks.

3

Erect the tower brackets

The tower brackets areerected in free cantilever mode bya 400t crawler crane. A fixedconnection is created against thetower shaft to support the partiallyerected bracket prior to installingthe first stay cable. A travellingworking platform provides accessto the splices and stay cableanchorages. Splices are formed by a combination of shear pins and CT bars allowing rapid splicingat height.

4

Erect the deck lifting frame

The upper cross beam isassembled element by element by400t crawler crane from the Northside and slid across the completedconcrete back span by horizontallymounted SLU strand jacks. Once fully assembled it is lifted by acombination of lifting towers and SLUstrand jacks and the cantilever beamsare threaded underneath by crane.

5

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TECH SHOW


Use VSL jacks to lift at

10m/hour for two days

The main heavy lift utilizes 16 SLU-330 strand jacks and 4 SLU-220 forthe vertical movement combinedwith 6 SLU-70 and 12 high capacitylong stroke jacks for the horizontalmovements. A lifting speed of morethan 10m/h ensures that sufficienttime is available for the requiredhorizontal movements and relatedactivities during the two day liftingoperation.

6

VSLNews2-2007 30/11/07 16:03

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Consider typhoons

The deck is guided during the lift through a system of guiderollers against the tower and the backspan falsework. To allow tyingoff the decks over night or in storm wind conditions, three emergencyrestraint positions are provided where the decks can be rigidlyconnected to the back span falsework and clamped to the tower shaft.Full typhoon restraint is only provided in final position.

7

Monitor with BRAVO

The simultaneous operation of the 8 liftingpoints with a total of 20 strand jacks required the useof the BRAVO lift control system to ensuresynchronized movement of the two carriageways.The system monitors the level differences betweenthe lifting points as well as the lifting pressures. All lifting operations are controlled from a centralcommand unit. The build-up of the lifting loadrequired a well engineered adjustment sequencebetween the various load bearing components of thetower bracket and in the back span falsework.

8

Lift the cross girders

The cross girders are liftedone-by-one by a pair of SLU-70strand jacks supported by a liftingbeam. Once in position the crossgirders are suspended by PT barsand the strand jacks are transferredto the next location.

9

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34

TECH SHOW


Erect the main span

segments

Four diamond shaped erectiongantries fitted with high capacitydiesel winches are used to lift themain span segments. They are pre-assembled on the back span steeldeck before the heavy lift and liftedtogether with the decks. The twogantries of each cantilever operatein tandem to lift the deck segmentsweighing 600t each.

10

Load transfer

The heavy lift system isdesigned to keep the deckssuspended during several monthswhile the cross girders are weldedand the permanent stay cables areinstalled. Critical elements such asthe deck connections and the strandanchorages have been detailed forimproved fatigue behaviour.The final load transfer is achieved bystressing the permanent stay cablesand subsequent de-tensioning of thelifting strand bundles.

11

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35

C R E AT I N G S O L U T I O N S T O G E T H E R

www.vsl.com

TAIWANVSL Taiwan Ltd.TAIPEIPhone: +886 2 2759 6819Fax: +886 2 2759 6821

THAILANDVSL (Thailand) Co. Ltd.BANGKOKPhone: +66 2 679 76 15 - 19Fax: +66 2 679 76 45

TURKEYMega Yapi Construction & Trade Co. LtdANKARAPhone: +90 312 490 90 66Fax: +90 312 490 90 55

VIETNAMVSL Vietnam Ltd.HANOIPhone: +84 4 976 50 88Fax: +84 4 976 50 89

Ho Chi Minh CityPhone: +84 8 8106 817Fax: +84 8 8106 818

Australia

VSL Australia Pty. Ltd.NEW SOUTH WALESPhone: +61 2 9 484 59 44Fax: +61 2 9 875 38 94

QUEENSLANDPhone: +61 7 3265 64 00Fax: +61 7 3265 75 34

VICTORIA and SOUTHERNPhone: +61 3 979 503 66Fax: +61 3 979 505 47

Americas

ARGENTINAVSL Sistemas Especiales deConstrucción Argentina SABUENOS AIRESPhone: +54 11 4326 06 09Fax: +54 11 4326 26 50

CHILEVSL Sistemas Especiales deConstrucción S.A.SANTIAGOPhone: +56 2 571 67 00Fax: +56 2 233 67 39

COLOMBIASistemas Especiales de Construcción Ltda.BOGOTAPhone: +57 1 620 96 34Fax: +57 1 620 58 16

MEXICOVSL Corporation Mexico S.A de C.VMEXICOPhone: +52 5 396 86 21Fax: +52 5 396 84 88

UNITED STATESVStructural LLCBALTIMORE, MDPhone: +1 410 850 7000Fax: +1 410 850 4111

VENEZUELAGestión de Obras y Construcciones C.A.CARACASPhone: +58 212 941 86 75Fax: +58 212 941 86 75

Middle East

UNITED ARAB EMIRATESVSL Middle East LLCDUBAI, UAEPhone: +971 4 333 6262Fax: +971 4 333 0008

Africa

EGYPTMatrix Engineering CompanyCAIROPhone: +20 2 344 19 00Fax: +20 2 346 04 57

MOROCCORenfor-BatTANGIERPhone: +212 39 95 80 87Fax: +212 39 95 80 85

SOUTH AFRICATsala-RMS Construction Solutions (Pty) LtdJohannesburgPhone: +27 11 878 6820Fax: +27 11 878 6821

Europe

AUSTRIAGrund-Pfahl- und Sonderbau GmbHHIMBERGPhone: +43 2235 87 777Fax: +43 2235 86 561

CZECH REPUBLICVSL Systems (CZ) Ltd.PRAGUEPhone: +420 2 51 09 16 80Fax: +420 2 51 09 16 99

FRANCEVSL France S.A.LABÈGEPhone: +33 05 61 00 96 35Fax: +33 05 61 00 96 62

GERMANYVSL Systems GmbHBERLINPhone: +49 30 53 01 35 32Fax: +49 30 53 01 35 34

GREAT BRITAINVSL Systems (UK) Ltd.BEDFORDSHIREPhone: +41 58 456 30 30Fax: +41 58 456 30 35

NETHERLANDSHeijmans Beton en Waterbouw B.V.ROSMALENPhone: +31 73 543 66 02Fax: +31 73 543 66 11

NORWAYVSL Norge A/SSTAVANGERPhone : +47 51 52 50 20Fax : +47 51 56 27 21

PORTUGALVSL Sistemas Portugal Pre-Esforço, Equipamento e Montagens S.A.S. DOMINGOS DE RANAPhone: +351 21 445 83 10Fax: +351 21 444 63 77

VSL GEOSistemas de Aplicação em Geotecnia SAS. DOMINGOS DE RANAPhone: + 351 21 445 83 10Fax: + 351 21 445 83 28

Asia

BRUNEI VSL Systems (B) Sdn. Bhd.BRUNEI DARUSSALAMPhone: +673 2 380 153 / 381 827Fax: +673 2 381 954

CHINA PRCVSL (China) Engineering Corp., Ltd.HEFEIPhone: +86 551 382 29 18Fax: +86 551 382 28 78

HONG KONGVSL Hong Kong Ltd.CHAI WANPhone : +852 2590 22 88Fax : +852 2590 02 90

Intrafor Hong Kong Ltd.CHAI WANPhone : +852 2836 31 12Fax : +852 2591 61 39

FT Laboratories Ltd.KOWLOON BAYPhone: +852 2758 48 61Fax: +852 2758 89 62

INDIAVSL India PVT Ltd.CHENNAIPhone: +91 44 4225 11 11Fax: +91 44 4225 10 10

INDONESIAPT VSL IndonesiaJAKARTAPhone: +62 21 570 07 86Fax: +62 21 573 12 17

JAPANVSL Japan CorporationTOKYOPhone: +81 3 3346 8913Fax: +81 3 3345 9153

KOREAVSL Korea Co. Ltd.SEOULPhone: +82 2 553 8200Fax: +82 2 553 8255

MALAYSIAVSL Engineers (M) Sdn. Bhd.KUALA LUMPURPhone: +603 7981 47 42Fax: +603 7981 84 22

PHILIPPINESVSL Philippines Inc.PASIG CITYPhone: +632 672 17 03Fax: +632 672 13 95

SINGAPOREVSL Singapore Pte. Ltd.SINGAPOREPhone: +65 6559 12 22Fax: +65 6257 77 51

SPAINCTT StrongholdBARCELONAPhone: +34 93 289 23 30Fax: +34 93 289 23 31

VSL-SPAM, S.A.BARCELONAPhone: +34 93 846 70 07Fax: +34 93 846 51 97

SWEDENInternordisk Spännarmering ABVÄSTERHANINGEPhone: +46 8 5007 3820Fax: +46 8 753 49 73

SWITZERLANDVSL (Switzerland) Ltd.SUBINGENPhone: +41 58 456 30 30Fax: +41 58 456 30 35

VSL (Suisse) SASAINT LEGIERPhone: +41 58 456 30 00Fax: +41 58 456 30 95

HEADQUARTERS

VSL International Ltd.

Scheibenstrasse 70 – Bern

CH-3014 – Switzerland

Phone: +41 58 456 30 30

Fax: +41 58 456 30 35 VSL LOCATIONS

VSLNews2-2007 30/11/07 16:04

Y O U R S O L U T I O N P A R T N E RVSL operates through 35 subsidiaries as a world-wide network. The company has adapted post-tensioning principles

to civil structures such as LNG tanks, plants, tunnels, off-shore platforms, dams -and stay cables. In addition, the

group's scope of works covers rock and soil anchors, stabilized walls, precasting, formwork systems, launching

gantries, heavy lifting, bearings, repair works, monitoring, deep foundation and soil engineering activities. VSL offers

skilled and trained specialists; an experienced technical center able to benchmark new methods, new equipment and

new materials; specialist equipment designed as modular as possible; innovative contracting approach to focus with

the Main Contractor on what is “best for project”. www.vsl.com

VSLNews2-2007 30/11/07 16:03

repair with cfrp active strengthening

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